Components:

(1) Naphthalene, C₁₀H₈; [91-20-3] NIST WebBook
(2) Sodium chloride, NaCl; [7647-14-5] NIST WebBook
(3) Water, H₂O; [7732-18-5] NIST WebBook

Original Measurements

Schwarz, F. P.; J. Chem. Eng. Data. 1977, 22, 273-7.

Variables:

Ambient temperature: 8.6 - 31.8 °C
Acidity: Salnity: 30 g(2)/kg sln
Salnity: 30 g(2)/kg sln

Prepared by:

D. Mackay, W.Y. Shiu

Method/Apparatus/Procedure:

The solubility of naphthalene in NaCl solution was determined by fluorescence and UV absorption measurements. In the fluorescence method, saturated solution was prepared by ading excess amount of naphthalene to an air-tight 1x1 cm quarts fluorescence cell containing 5 mL salt solution. The cell was rotated at 20 rpm for at least 72 hr in a thermostatted water bath and then its fluorescent intensity was measured at 350 and 315 nm. The Spectrofluorimeter employed a ratio-photon counting mode where naphthalene concentration was linearly related to the fluorescence signal. The UV method was used to obtain the absorptivity of naphthalene in ethanol therefore provide an absolute solubility scale for the fluorescence method.

Source and Purity of Materials:

1. Naphthalene: purity > 99 mole%
2. Sodium chloride: reagent grade
3. Water: distilled over a KMnO₄- NaOH solution and passed through a Sephadex column.

Estimated Errors:

Ambient temperature: ±0.1°C
Mass concentration (m/v) (1): ±3.3%